The data was presented today at an international conference, DNA Vaccines 2012, in San Diego, Ca, by Dr. Christian H. Ottensmeier, MD, PhD, the trial's principal investigator and Professor of Experimental Cancer Research at the University of Southampton, UK. These interim results, from eight patients, are part of a phase II trial that will enroll 31 patients in its chronic myelogenous leukemia (CML) arm. To date, 14 CML patients have been enrolled while another 13 unvaccinated CML patients have been enrolled to serve as a control group. The vaccine has been shown to be safe overall and well-tolerated in the trial subjects. A detailed analysis of T cell immune responses as well as the impact of the vaccination on the molecular marker, BCR-ABL, which is a specific chromosomal abnormality that is associated with chronic myelogenous leukemia (CML) disease, will be performed.

As a result of the favorable safety and immunogenicity profiles observed in the CML vaccinated group, the trial is now open to enroll the acute myeloid leukemia (AML) clinical trial arm, with a total target of 37 subjects in each of the vaccinated and control groups.

This open-label, multi-center phase II clinical trial is evaluating a DNA vaccine-based immune therapy to treat these two types of leukemia. The DNA vaccine, developed by the University of Southampton, is delivered using Inovio's proprietary electroporation technology. Financial support for the trial is being provided by the UK research charity Leukaemia and Lymphoma Research (LLR) and the Efficacy and Mechanisms Evaluation (EME) programme (which is funded by the UK Medical Research Council and managed by the UK National Institute for Health Research).

Leukemia is a cancer of the bone marrow and blood that accounts for at least 300,000 new cases and 222,000 deaths worldwide each year - a very high death rate. Wilms' Tumor gene 1 (WT1) is highly associated with these types of cancer. Preclinical data from mice showed strong induction of antigen-specific CD8+ T cells and the ability to kill human tumor cells expressing WT1. This is the first study to combine DNA vaccination with electroporation delivery of WT1 antigens with the goal of stimulating high and durable levels of immune responses, in particular T cells, which are considered critical for improving clinical outcomes for this disease.

The principal investigator of this study, Dr. Ottensmeier, said, "These preliminary data show strong vaccine-induced immune responses in vaccinated subjects in the CML arm. We are looking forward to enrolling and testing the vaccine's impact in AML patients, who currently have limited treatment options and a low rate of progression free survival."

In this ongoing phase II trial, all participants initially receive six doses of two DNA vaccines (called p.DOM-WT1-37 and p.DOM-WT1-126) delivered at four week intervals. Vaccine responders may continue with booster vaccinations every three months out to 24 months. An additional 60-75 AML/CML patients are being enrolled across the two arms as non-vaccinated controls for comparison. The primary endpoints are molecular responses to a disease marker called BCR-ABL in CML patients and time to disease progression in AML patients. The study is also monitoring WT1 transcript levels, immune responses to the WT1 antigen, time to progression and overall survival, and two-year survival in the AML group. The trial is taking place at hospitals in Southampton, London and Exeter. Regulatory approval to start this clinical study was provided by the UK Medicines and Healthcare Products Regulatory Authority (MHRA) and Gene Technology Advisory Committee (GTAC).

Leukemia is a malignant disease (cancer) of the bone marrow and blood characterized by the uncontrolled accumulation of blood cells. Leukemia accounts for at least 300,000 new cases and 222,000 deaths worldwide each year. This high ratio of deaths-to-cases (74%) reflects the poor prognosis of leukemia in many parts of the world, where the somewhat complex treatment regimes are not available. Approximately 45,000 new cases of leukemia were diagnosed in 2008 in the US, with 20,000 deaths. This represents 3% of all cancers in the United States, and 30.4% of all blood cancers. It is estimated that approximately $3 billion is spent in the United States each year to treat leukemia.

There are five types of leukemia based on rate of development and types of blood cells affected. Two of these are being evaluated in the study discussed in this release: 1) Acute myeloid leukemia (AML), a cancer of the myeloid line of blood cells, is characterized by rapid growth of abnormal white blood cells that accumulate in the bone marrow and interfere with the production of normal blood cells. AML is the most common acute leukemia affecting adults and its incidence increases with age. Only about one-third of those between ages 18-60 who are diagnosed with AML can be cured. With conventional chemotherapy 70% of the patients in the group under study will relapse within two years and current therapy is devastating in older adults; and 2) Chronic myeloid leukemia (CML) is a type of cancer that causes the body to produce large numbers of immature and mature white blood cells (myelocytes). Approximately 85% of patients with CML are in the chronic phase at the time of diagnosis. Ultimately, in the absence of curative treatment, the disease progresses to an accelerated phase where median survival is around 3-5 years. Chronic myeloid leukemia can occur at any age, but it more commonly affects middle-aged and older people.

About the University of Southampton

The University of Southampton is a leading UK teaching and research institution with a global reputation for leading-edge research and scholarship across a wide range of subjects in engineering, science, social sciences, health and humanities.

With over 23,000 students, around 5000 staff, and an annual turnover well in excess of £435 million, the University of Southampton is acknowledged as one of the country's top institutions for engineering, computer science and medicine. We combine academic excellence with an innovative and entrepreneurial approach to research, supporting a culture that engages and challenges students and staff in their pursuit of learning.

The University is also home to a number of world-leading research centres including the Institute of Sound and Vibration Research, the Optoelectronics Research Centre, the Web Science Trust and Doctoral training Centre, the Centre for the Developmental Origins of Health and Disease, the Southampton Statistical Sciences Research Institute and is a partner of the National Oceanography Centre at the Southampton waterfront campus.

About Inovio Pharmaceuticals, Inc.

Inovio is revolutionizing vaccines to prevent and treat today's cancers and challenging infectious diseases. Its SynCon® vaccines are designed to provide universal cross-strain protection against known as well as newly emergent unmatched strains of pathogens such as influenza. These synthetic vaccines, in combination with Inovio's proprietary electroporation delivery, have been shown in humans to generate best-in-class immune responses with a favorable safety profile. Inovio's clinical programs include phase II studies for cervical dysplasia, leukemia and hepatitis C virus and phase I studies for influenza and HIV. Partners and collaborators include the University of Pennsylvania, Merck, ChronTech, National Cancer Institute, U.S. Military HIV Research Program, NIH, HIV Vaccines Trial Network, University of Southampton, US Dept. of Homeland Security and PATH Malaria Vaccine Initiative. More information is available at www.inovio.com.

This press release contains certain forward-looking statements relating to our business, including our plans to develop electroporation-based drug and gene delivery technologies and DNA vaccines and our capital resources. Actual events or results may differ from the expectations set forth herein as a result of a number of factors, including uncertainties inherent in pre-clinical studies, clinical trials and product development programs (including, but not limited to, the fact that pre-clinical and clinical results referenced in this release may not be indicative of results achievable in other trials or for other indications, that the studies or trials may not be successful or achieve the results desired, that pre-clinical studies and clinical trials may not commence or be completed in the time periods anticipated, that results from one study may not necessarily be reflected or supported by the results of other similar studies and that results from an animal study may not be indicative of results achievable in human studies), the availability of funding to support continuing research and studies in an effort to prove safety and efficacy of electroporation technology as a delivery mechanism or develop viable DNA vaccines, the adequacy of our capital resources, the availability or potential availability of alternative therapies or treatments for the conditions targeted by the company or its collaborators, including alternatives that may be more efficacious or cost-effective than any therapy or treatment that the company and its collaborators hope to develop, evaluation of potential opportunities, issues involving product liability, issues involving patents and whether they or licenses to them will provide the company with meaningful protection from others using the covered technologies, whether such proprietary rights are enforceable or defensible or infringe or allegedly infringe on rights of others or can withstand claims of invalidity and whether the company can finance or devote other significant resources that may be necessary to prosecute, protect or defend them, the level of corporate expenditures, assessments of the company's technology by potential corporate or other partners or collaborators, our ability to secure new partnerships and collaborations, capital market conditions, the impact of government healthcare proposals and other factors set forth in our Annual Report on Form 10-K for the year ended December 31, 2011, our Form 10-Q for the quarter ended September 30, 2012, and other regulatory filings from time to time. There can be no assurance that any product in Inovio's pipeline will be successfully developed or manufactured, that final results of clinical studies will be supportive of regulatory approvals required to market licensed products, or that any of the forward-looking information provided herein will be proven accurate.